var fs=require("fs");
var data='';

var readerStream=fs.createReadStream('input.txt')
readerStream.setEncoding('UTF8');

readerStream.on('data',function(chunk){
    data+=chunk;
});

readerStream.on('end',function(){
    console.log(data);
});

readerStream.on('error',function(err){
    console.log(err.stack);
});

console.log("程序执行完毕");